$8 Trillion Internet

In the last 5 years, the internet accounted for 21% of GDP growth in the world's largest economies. The internet as a sector is larger than these countries' industries in agriculture or energy. It makes up 3.4% of GDP in large, developed economies. Internet activities is defined as private consumption, private investment, public expenditure, and trade. The US leads in the online industry, claiming 30% of global Internet revenue. Sweden leads in the Internet's contribution to GDP at 6.3% of its economy online.

http://www.theatlantic.com/business/archive/2011/11/the-8-trillion-internet-mckinseys-bold-attempt-to-measure-the-e-conomy/247963/